Mitsubishi Reviews

If the warning is being shown when the engine is first started (and therefore, patently not overheating) the fault is likely to be with an engine sensor that tells the computer the engine temperature. This model is known for this fault.

However, if the engine really is overheating, the possible causes are many and could be a stuck thermostat, a blocked radiator, a leak in the cooling system, a failed EGR valve, a failing water pump, or perhaps even something less obvious like a blown head gasket.

So the first step is to determine whether the engine really is overheating or not and go from there. An experienced mechanic will tackle each possibility in turn, but make sure they’re aware of the sensor problem with this model.

I’d agree that 13.3 litres per 100km is a bit of the high side, but to put it into perspective, you need to forget about the factory claim of 8.0 litres per 100km. That figure is determined by a laboratory test, not real-world driving and rare indeed is the vehicle that can match its test figure with its real-world number.

I would expect a number closer to 11 litres per 100km for this vehicle, but there are a lot of variables at work here. For instance, does the vehicle have a roof rack? Have you fitted a bull-bar? Does the vehicle roll on standard sized wheels and tyres, or are they taller, aftermarket tyres which increase rolling diameter and throw the standard gearing out?

The latter – in particular – can affect fuel consumption in a huge way, as can how you drive the car. High speeds or urban driving will also rapidly increase fuel consumption. If you’re still concerned, have the vehicle tuned to see if that makes a difference.

This has been an ongoing problem for many owners of many different makes and models of cars fitted with Diesel Particulate Filters (DPFs). The process of dumping fuel into the engine is designed to get the exhaust system hot enough for the DPF regeneration (self-cleaning) to take place. But a car that travels 500km per week really shouldn’t need this as the exhaust system should be getting hot enough in the normal course of things.

Either way, if you constantly have excess fuel being dumped into the engine, some of it will find its way into the sump (as you’ve discovered). That’s when the check engine light signals the problem, but in the meantime, you’re also driving around with engine oil diluted by the extra fuel. And that’s when engine wear can occur because diluted oil isn’t able to protect the engine’s metal parts as well as it should.

It could be that the car’s sensors are giving the computer the wrong information on how hot it’s getting, and/or how dirty the DPF is. Perhaps the DPF itself is damaged to the point where it won’t regenerate fully. A diesel specialist would be a good place to start, as this problem is hardly unknown these days.